Exposure to entertainment media (TV, movies, music, video games and the Internet) has been associated with key adolescent health outcomes, including obesity, alcohol, and tobacco use, by a large body of research evidence. This research has been limited by weak data collection measures and a narrow focus on television viewing. Media use has grown and diversified dramatically, with youth growing up in media-rich environments, often multitasking with 2 or more media simultaneously. The broad, long-term objective of this study is to validate Measurement of Youth Media Exposure (MYME), a multimethod instrument designed to obtain a more sensitive and comprehensive assessment of adolescent use of and exposure to entertainment media. Its specific aims are to test the feasibility and acceptability of MYME, to assess MYME's reliability and validity, and to evaluate MYME's ability to predict key adolescent health risks of overweight, alcohol use, and tobacco smoking. MYME combines established, complementary methods of Recall Estimate (RE), Time-Use Diary (TUD), and Momentary Sampling (MS) so the strengths of each compensate for limitations of others. 150 youth 13 to 15 years old will complete a RE of their media exposure, alcohol and tobacco use status and have their height and weight measured on enrollment (RE0). They will carry a PDA and video camcorder for 1 week, responding to random signals by answering questions on their media exposure, including content, context and their state of mind, and video recording their environments, activities, and media exposures. On a randomly selected weekday and weekend day, participants will keep a 24 hour TUD of their activities, including media use, content, and context of use. At the end of the week, participants will return their equipment and execute RE1, recalling their media use over the past week. They will complete the full MYME protocol again after 1 week off, so that each MYME component and the whole measure can be evaluated for reliability and validity. One year after completing MYME, participants will be weighed and measured and will again complete RE0 assessing media exposure and substance use. This study will evaluate a more sensitive, comprehensive and accurate measurement of youth media exposure and key health outcomes with the goal of developing more effective prevention programs. PUBLIC HEALTH RELEVANCE: Young people's exposure to media has been linked to obesity, smoking, and alcohol use. However, it has been difficult to definitively characterize the relationships and to develop effective prevention and intervention strategies because research methods have focused on obsolete media technologies and use patterns. The proposed research will test an innovative method of obtaining a more sensitive and comprehensive measurement of media exposure in the multimedia environments and multitasking lifestyles of today's youth.